feat(pyamber): skip duplicate output writers

[carloea2]

What changes were proposed in this PR?

Start output storage writers only when the output port is first registered. Duplicate registration keeps the existing port and writer set.

Any related issues, documentation, discussions?

Closes #8277

How was this PR tested?

Added coverage proving that duplicate port registration does not start replacement writers, alongside the existing positive writer-setup coverage.

C:\Users\carlo\texera\texera\.venv312\Scripts\python.exe -c "import sys,pytest; sys.path[:0]=[r'C:\Users\carlo\texera\texera-worktrees\investigate-bug74\amber\src\main\python',r'C:\Users\carlo\texera\texera\amber\src\main\python']; raise SystemExit(pytest.main([r'amber\src\test\python\core\architecture\packaging\test_output_manager.py','-p','no:cacheprovider','-q']))"

C:\Users\carlo\texera\texera\.venv312\Scripts\ruff.exe check amber/src/main/python/core/architecture/packaging/output_manager.py amber/src/test/python/core/architecture/packaging/test_output_manager.py

C:\Users\carlo\texera\texera\.venv312\Scripts\ruff.exe format --check amber/src/main/python/core/architecture/packaging/output_manager.py amber/src/test/python/core/architecture/packaging/test_output_manager.py

All 40 tests passed. Ruff checks passed.

Was this PR authored or co-authored using generative AI tooling?

Generated-by: Codex

[github-actions]

Backport auto-label report

This fix: PR was checked against each actively-supported release branch. release/* labels drive the post-merge backport, so add or remove one to change where this fix lands.

Release branch	Analysis
⚠️ release/v1.3	Not labeled automatically — none of the files this PR modifies exist on this branch (amber/src/main/python/core/architecture/packaging/output_manager.py, amber/src/test/python/core/architecture/packaging/test_output_manager.py). The fix may target code that isn't on this release, or the files were moved/renamed after the branch was cut. Please check and add release/v1.3 by hand if this fix should be backported here.
✅ release/v1.2	Already labeled — this fix is queued to backport here.

Auto-label run.

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @aglinxinyuan, @eugenegujing
  You can notify them by mentioning @aglinxinyuan, @eugenegujing in a comment.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.93%. Comparing base (50321e4) to head (edd5057).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8278   +/-   ##
=========================================
  Coverage     93.93%   93.93%           
  Complexity     4761     4761           
=========================================
  Files          1191     1191           
  Lines         48308    48308           
  Branches       5377     5377           
=========================================
  Hits          45378    45378           
  Misses         1495     1495           
  Partials       1435     1435           

Flag	Coverage Δ		*Carryforward flag
access-control-service	81.00% <ø> (ø)		Carriedforward from 50321e4
agent-service	99.32% <ø> (ø)		Carriedforward from 50321e4
amber	90.02% <ø> (ø)		Carriedforward from 50321e4
computing-unit-managing-service	73.67% <ø> (ø)		Carriedforward from 50321e4
config-service	86.86% <ø> (ø)		Carriedforward from 50321e4
file-service	87.91% <ø> (ø)		Carriedforward from 50321e4
frontend	96.41% <ø> (ø)		Carriedforward from 50321e4
notebook-migration-service	79.31% <ø> (ø)		Carriedforward from 50321e4
pyamber	98.87% <100.00%> (ø)
workflow-compiling-service	77.19% <ø> (ø)		Carriedforward from 50321e4

*This pull request uses carry forward flags. Click here to find out more.

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[github-actions]

⚠️ Benchmark changes need a look

🟢 0 better · 🔴 10 worse · ⚪ 5 noise (<±5%) · 0 without baseline

Compared against main 50321e4 benchmarked on this same runner, so the delta is largely free of cross-runner hardware noise. The "7d avg" column still reflects the gh-pages dashboard. Treat <±5% as noise unless repeated.

Dashboard · Run

	config	throughput	MB/s	latency	max Δ latest / 7d
🔴	bs=10 sw=10 sl=64	377	0.23	25,787/39,870/39,870 us	🔴 +11.5% / 🔴 +155.9%
🔴	bs=100 sw=10 sl=64	932	0.569	106,397/147,293/147,293 us	🔴 +19.3% / 🔴 +37.3%
⚪	bs=1000 sw=10 sl=64	1,093	0.667	903,589/1,058,874/1,058,874 us	⚪ within ±5% / 🟢 -8.0%

Baseline details

Latest main 50321e4 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	377 tuples/sec	424 tuples/sec	787.98 tuples/sec	-11.1%	-52.2%
bs=10 sw=10 sl=64	MB/s	0.23 MB/s	0.259 MB/s	0.481 MB/s	-11.2%	-52.2%
bs=10 sw=10 sl=64	p50	25,787 us	23,133 us	12,593 us	+11.5%	+104.8%
bs=10 sw=10 sl=64	p95	39,870 us	36,374 us	15,579 us	+9.6%	+155.9%
bs=10 sw=10 sl=64	p99	39,870 us	36,374 us	18,786 us	+9.6%	+112.2%
bs=100 sw=10 sl=64	throughput	932 tuples/sec	987 tuples/sec	1,008 tuples/sec	-5.6%	-7.5%
bs=100 sw=10 sl=64	MB/s	0.569 MB/s	0.603 MB/s	0.615 MB/s	-5.6%	-7.5%
bs=100 sw=10 sl=64	p50	106,397 us	100,973 us	100,701 us	+5.4%	+5.7%
bs=100 sw=10 sl=64	p95	147,293 us	123,444 us	107,244 us	+19.3%	+37.3%
bs=100 sw=10 sl=64	p99	147,293 us	123,444 us	116,122 us	+19.3%	+26.8%
bs=1000 sw=10 sl=64	throughput	1,093 tuples/sec	1,085 tuples/sec	1,042 tuples/sec	+0.7%	+4.9%
bs=1000 sw=10 sl=64	MB/s	0.667 MB/s	0.663 MB/s	0.636 MB/s	+0.6%	+4.9%
bs=1000 sw=10 sl=64	p50	903,589 us	927,852 us	981,959 us	-2.6%	-8.0%
bs=1000 sw=10 sl=64	p95	1,058,874 us	1,018,444 us	1,023,080 us	+4.0%	+3.5%
bs=1000 sw=10 sl=64	p99	1,058,874 us	1,018,444 us	1,051,697 us	+4.0%	+0.7%

Raw CSV

config_idx,batch_size,schema_width,string_len,num_batches,total_ms,total_tuples,total_bytes,tuples_per_sec,mb_per_sec,lat_p50_us,lat_p95_us,lat_p99_us
0,10,10,64,20,531.03,200,128000,377,0.230,25786.88,39869.54,39869.54
1,100,10,64,20,2146.44,2000,1280000,932,0.569,106396.95,147293.44,147293.44
2,1000,10,64,20,18294.20,20000,12800000,1093,0.667,903588.86,1058873.61,1058873.61